[CT-01] Scaffold resource_credits contract — define types and storage keys

[yusuftomilola]

Overview

Create the initial scaffolding for the resource_credits Soroban contract inside contracts/sandbox/resource_credits/. This includes the project structure, core data types, storage key enum, and error definitions — following the same conventions as the existing workspace_booking and payment_escrow contracts.

Acceptance Criteria

• contracts/sandbox/resource_credits/Cargo.toml is created with correct Soroban SDK dependency
• src/lib.rs is created with #![no_std], contract struct, and empty #[contractimpl] block
• src/types.rs defines CreditBalance, CreditTransaction, and TransactionType structs/enums
• src/errors.rs defines an Error enum with at least: AdminNotSet, AlreadyInitialized, Unauthorized, InsufficientBalance, InvalidAmount, AccountNotFound
• DataKey enum in lib.rs covers: Admin, PaymentToken, Balance(Address), TotalSupply, TransactionHistory(Address)
• initialize(env, admin, payment_token) function is stubbed out
• Code compiles with cargo build

[BigBen-7]

@BigBen-7 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

can i work on this?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @BigBen-7 to this issue.

[drips-wave]

Congratulations, @BigBen-7! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

🧑‍💻 @BigBen-7: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

This issue has been completed by @BigBen-7 as part of the Stellar Wave Program's 4th Wave 🥳

😎 @BigBen-7: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.